Substituted pyridazones



United States Patent 3,210,353 SUBSTITUTED PYRIDAZONES Franz Reicheneder and Karl Dury, Ludwigshafen (Rhine), Germany; Johanna Maria Dury, Kirchheimbolanden, Germany, legal representative of Karl Dury, deceased; and Adolf Fischer, Mutterstadt, Pfalz, Germany, assignors to Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Germany No Drawing. Filed Mar. 27, 1964, Ser. No. 355,414 Claims priority, application Germany, Nov. 21, 1958, B 51,155; Mar. 25, 1961, B 61,873 Claims. (Cl. 260250) This application constitutes a continuation-in-part of each of our :copending applications, Serial No. 854,276, filed November 20, 1959, and Serial No. 129,541, filed August 7, 1961.

The present invention relates to new substituted pyridazones.

It has already been known to use s-triaz-ine derivatives or diazines or benzodiazines as Weedkillers. They have the disadvantage, however, that they damage not only the weeds but also crop plants, that their action is initiated only slowly and lasts for an undesirably long period.

It is an object of the invention to provide new and valuable pyridazones having good selective herbicidal activity.

The new pyridazones have the general formula:

wherein R is a substituent selected from the group consisting of hydrogen, a-hydroxy-B-trichloroethyl, acetyl, chloroacetyl, dichloroacetyl, trichloroacetyl, propionyl, chloropropionyl, dichloropropionyl, carbamyl, lN-phenylcarbamyl and N-3-chlorophenyl-earbamyl.

The compounds according to the invention have an outstandingly good Weed *ki'lling action. A special adventage, as compared with diazine and triazine derivatives, resides in the selective destruction of Weeds among crop plants, such as onions =01- cereals, and in the shortened after-effects. In suitable dosages, the agents according to this invention may also be used for the total destruction of all plants and 'for the prevention of undesirable vegetation. The shortening of the period of after-action as compared with triazine derivatives, which is very desirable :by reason of the risk of a subsequent injury to crop plants which are later sown or planted, can probably be explained by the ready degradation of the substances in the soil by hydrolytic splitting of the CO4N linkage of the pyridazones. A further advantage of the agents according to this invention resides in the more rapid initiation of their action as compared with diazine and triazine derivatives.

The compounds according to this invention are also useful for bringing about other etfects on plant growth, especially the defoliation of plants, the acceleration of the ripening process by premature desiccation of plants, for example in the case of potato cultivation, and also the reduction of fruit formation, retardation of blossoming, and also prolongation of the cropping periods and the storability. In suitable concentrations, the agents according to this invention may also be used in some cases as agents for promoting germination and root formation.

The pyridazones according to this invention are prepared in a manner known per se by the reaction of the corresponding chlorine-substituted pyridazones with the nitrogenous compounds in question; for example l-phenyl- 4-amino-5-chloropyridazone-(6) is obtain-ed by reaction of 1-phenyl-4,5-dichloro-pyridazone-(6) (obtainable by the process described in US. specification 'No. 2,628,181 from mucochloric acid and phenyl hydrazine by splitting off water with the aid of elevated temperature in glacial acetic acid) with ammonia in aqueous suspension under pressure. The pyridazones substituted in l-position by hydrogen or alkyl radicals are obtained in a corresponding way from mucochloric acid and hydrazine hydrate or monoalkyl hydrazines and subsequent reaction of the 4,5-dihalogenpyridazones (6) thus obtained with ammonia or amines substituted .by organic radicals.

Since all other compounds according to this invention can be prepared by an analogous process, the said preparation will now be described in greater detail:

1,000 parts by weight of 1-phenyl-4,5-dichloropyridazone-'(6) (prepared for example according to the said US. specification No. 2,628,181) are mixed in a pressure vessel holding 8 liters, with 4,000 parts of water and 600 parts of anhydrous ammonia are forced into the mixture under pressure. Then the 'vessel is heated for 6 hours at i "C, the pressure rising to 40 atmospheres. The reaction product is then allowed to cool and decompressed and the pressure vessel flushed repeatedly with nitrogen. The water is then separated from the solid substance and the latter washed repeatedly with dilute hydrochloric acid and then with water. lBy crystallization from methanol, 58 8 parts of 1-phenyl 4-amino 5-chloropyridazone (6) with the melting point 202 to 204 C are obtained.

Analysis.-C H ON Cl, calculated: C, 54.25; H, 3.62; N, 18.95; Cl, 16.05. Found: C, 54.62; H, 4.08; N, 19.26; Cl, 15.9.

The other compounds to be used according to this invention are obtained analogously. For the reaction with 11-phenyl-4,5-dichloropyridazonel(6) we prefer to use primary and secondary amino compounds. It should be noted that the less volatile amines can also be reacted without the use of a pressure vessel and that an excess of amine may be used as solvent in the case of amino compounds having a boiling point above 100 C.

The new pyridazones may be prepared in known manner for example by reaction of 1-phenyl-4-amino-S-chloropyridazone-(6) with chloral or acids or acid derivatives, for example acid chlorides, advantageously in a solvent, for example dirnethylformamide. The new compounds may further be prepared by reaction of 1-phenyl-4-amino- 5-ch1oropyridazone-(6) with isocyanates. For example 1 phenyl 4 chloroacetylamino 5 chloropyridazone- (6) is obtained by reaction of 1-phenyl-4-amino-5-chloropyridazone-6 with chloroacetyl chloride. N-phenyl-N'- (1-phenyl-5-chloropyridaz-6-on-4-yl)-urea is obtained by reaction of 1-phenyl-4-amino-5-chloropyridazone-( 6) with phenyl isocyanate.

The production of the chloroacetylamino compound is described in greater detail as follows:

22 parts of 1-phenyl-4-amino-5-chloropyridazone-(6) of the melting point 202 to 204 C. is dissolved hot in 20 parts of N-methylpyrrolidone in an agitated vessel. 11 parts of chloroacetyl chloride is dripped in with good stirring and the whole heated to 150 C. This temperature is maintained for 10 minutes, then the whole is allowed to cool slowly, diluted with water, the crystal slurry filtered 01T by suction and recrystallized from methanol. 27 parts of a White crystal powder of the melting point 124.5 to C. is thus obtained, which corresponds to a yield of 88% of the theory.

The other compounds to be used according to this invention may be obtained in an analogous manner. How- 3 ever the 1-phenyl-4-amino-5-chloropyridazone-(6) may be reacted directly with the free acids or the aldehydes in the presence or absence of solvents.

Compounds according to the invention are given by way of example in the following list:

Compound Mcltipr3 point,

l-phenyl-4-amino-5-chloropyridazonc- (6) 202 to 204 1phenyl-4,6,fifltrichloro-a-hydr0xy-ethy1amino-5- pyrldazoue-(G) 163 to 166 1-phenyl-4-acctylamino-5-chloropyridazone- (6) 1-phenyl-4-chloroacetylarnino-fi-chlor0pyridazonc-( The new compounds are outstandingly suitable for controlling undesirable plant growth. For this purpose, the plants to be controlled and/or the soil in which these plants grow are treated with a phytotoxic amount of the active substance. This amount depends on the special conditions of application, for example climate, type of soil, type of weeds, type of cultivated plants and stage of growth of the weeds and cultivated plants.

We have found that under normal conditions it is sufiicient to use amounts of 0.5 to 10 kilograms of active substance per hectare of surface to be treated. We pre fer to use an amount of 1 to 6 kilograms of active substance per hectare. The active substances may be used in the usual way. For example, they may be used in the form of their solutions in organic liquids, for example, diesel oil or kerosene, or as aqueous dispersions prepared from the active substances and Water using a dispersing agent, for example sodium lignin sulfonate, or formed by dilution of a concentrated dispersion with water.

They may also be used as dusting agents prepared by mixing the active substances with powdered materials.

We prefer the use of the following active substances because these are especially active:

1-phenyl-4-amino-5-chloropyri'dazone-(6)(M.P. 202 to 1 phenyl 4 3,3,5 trichloro a hydroxyethylamino- 5-chloropyridazone-(6)(M.P.163 to 166 C.)

1 phenyl 4 chloroacetylamino 5 chloropyridazone- (6)(M.P. 124.5 to 125 C.)

N phenyl N (1 phenyl 5 chloropyridaz 6- on-4-yl)-urea-(M.P. 174 to 175 C.)

The invention is further illustrated by, but not limited to, the following examples.

Example 1 Soil is treated with 1-phenyl-4-amino-S-chloropyridazone-(6) (melting point 202 to 204 C.) in amounts of 3 m8 kilograms per hectare. The active substance is sprayed onto the soil as an aqueous dispersion which has preferably been prepared by adding from 20 to 50%, with reference to the active substance, of a dispersing or emulsifying agent, for example sodium ligninsulfonate. It is true that from seeds of Sinapis alba, Panicum sanguinale, and Galium aparine, which have been sown in the soil thus treated, plants grow up to the cotyledon stage, but they have completely died after about three weeks.

Example 2 1-phenyl-4-amino 5 chloropyridazone-(6) (melting point 202 to 204 C.) is sprayed in amounts corresponding to 5 to 10 kilograms per hectare suspended in 1,000 liters of water onto the following plants in the greenhouse: Sinapis alba, Galium aparz'ne, Poa annua, Poly-i i in 500 liters of water.

gonum persicaria, Veronica agrestis and Lamium amplexicaule. After about three days, the plants exhibit a chlorotic lightening and begin to wither from the tips of the leaves. They are completely destroyed after four weeks.

Example 3 An area of arable soil which is infested mainly with the following weeds: Galinsoga parviflora, Raphanus raphanistrum, Sinapis alba, Lamium amplexicaule, F immria ofiicin'alis, Viciai hirsuta, Polygonum persicaria, Matricaria inodora, Poa annua, Atriplex patul'um, and Stel- Iaria media, is sprayed with 1-phenyl-4-amino-S-chloropyridazone-(6) (melting point 202 to 204 C.) in amounts of 10 to 20 kilograms per hectare suspended Most of the Weeds are completely destroyed after five weeks.

Example 4 Bean plants four to five weeks old are dusted with a powder made from 15 parts of 1-phenyl-4-amino-5- chloropyridazone-(6) (melting point 202 to 204 C.) and parts of ground clay. After four to eight days, these plants exhibit very marked leaf burning.-

Example 5 Rye, Avena fatua, Sinapis arvensz's, and lettuce are sown in adjacent double rows in open ground and immediately after sowing treated in separate parcels each 2 square meters in size with the following emulsions and dispersions in amounts of 1, 2.5 and 5 kilograms per hectare in 500 liters of Water:

Substance I: 3,4,5-trichloropyridazine Substance II: 3,4,5,6-tetrachloropyridazine Substance III: 1-phenyl-4-amino-5-chloropyridazone-(6) (melting point 202 to 204 C.).

From the following table the superior effect of phenylaminochloropyridazone as compared with the two chlorinated pyridazines can be clearly seen.

plants; 3=marked damage, but leaves not withering, whole plants damaged; 4=the greater part of the leaves and individual plants withered; 5=plants completely destroyed.

Example 6 Onions sown in open ground are treated, eight days after the tips of the same have pushed through the surface of the soil, in each hectare with dispersions, each of 1.3 kilograms in 500 liters of water, of (I) l-phenyl-4- amino-S-chloropyridazone-(6) (melting point 202 to 204 C.), (II) para-chlorophenyldimethylurea and (III) 2-chlor-4,6-bis-ethylamino-s-triazine. Six weeks later it is observed that the onions in the parcels treated with (1) exhibit good growth and no substantial damage, whereas those in the parcels treated with (II) and (III) are almost completely destroyed. As weedkillers all three chemical compounds are practically equivalent in effect. The following weeds are severely damaged in growth or completely destroyed: Mwtricariw inodora, Galinsoga parviflom, Stelglaria media, Sinapis arvensis, Spergula arvensis, Polygonum persz'caria, and Poa annuw.

Example 7 On each hectare of uncultivated land there are uniformly sprayed suspensions having each an amount of active u stance of 22 kilograms in 1,000 liters of water,

the active substances used being (I) 1-phenyl-4-dimethylaminO-S-chloropyridazone-(6) (melting point 89 to 90 C.) and (II) 2-chloro-4,6-bis-ethylamino-s-triazine. The plants on the uncultivated land are as follows: Hole-us mollis, HOlcas lanatas, Poa bulbosa, Loliam perenne, T araxacam ofifcinale, Aclzillea millefoliam, and Tanacetam valgare. In mainly dry weather, a clear leaf corroding action is observed even after six to eight days on the parcels treated with substance (I). On the contrary no herbicidal effect can be detected after the same period of time on the surfaces treated with substance (II).

Example 8 Seeds of peas, beetroot, carrots, onions, mustard and wild oats are sown in transverse rows in seed dishes (25 by 30 centimeters) filled with light sandy soil. After most of the plants have developed up to the cotyledon stage, an amount of finely grained mixture equivalent to the use of 3 kilograms of 1-phenyl-4-chloroacetylamino- 5-chloropyridazone-(6) and 197 kilograms of calcium nitrate per hectare is uniformly scattered over the plants and the soil in the dishes. Five weeks later it is found that the beetroot and onions have survived this treatment without growth inhibition. Peas show slight chlorotic damage to the edges of the leaves while wild oats, mustard and carrots are practically completely destroyed. Of the weeds which have come up between the cultivated plants, Galinsoga paraviflora, Matricaria ehamomilla, Urtica zu'ens, Poa annaa, Chenopodium album and Stellaria media are practically completely withered.

The following phenylpyridazones, when used in admixture with calcium nitrate with the same amount of active substance, have similar action:

1-phenyl-4-acetylamino-5-chloropyridazone- 6) 1-phenyl-4-dichloroacetylamino-5-chloropyridazone 6) 1-phenyl-4-trichl oroacetylamino-5-chloropyridazone-(6) l-phenyl-4-propionylamino-S-chloropyridazone- 6) 1phenyl-413-chloropropionylamino-S-chloropyridazone- 6) 1phenyl-41,0:-dichloropropionylamino-S-chloropyrid azone- (6) Example 9 Sugar beet plants in a cultivated area, after thinning out and hoeing the soil, are sprayed with 1-phenyl-4-B,B,,B- trichloro-a-hydroxy-ethylamino 5-chloropyridazone-(6), used in an amount equivalent to 4 kilograms of active substance dispersed in 1,000 liters of water per hectare. No fresh growth of weeds is observed between the individual rows up to the harvesting of the beetroot plants. The following weeds are destroyed as they come up or in the cotyledon stage: Uritica areas, Chenopodiam album, Galinsoga paraviflora, Poa annua and Panicum sanguinale. The beetroot plants suffer no damage by this treatment.

Example 10 1-phenyl-4-chloroacetylamino 5-chloropyridazone-(6) is sprayed in autumn in an amount equivalent to an application of 3 kilograms thereof dispersed in 1,000 liters of water per hectare onto a winter barley crop which is infested with Agrostis spica venti, Stellaria media and Galium aparine. After about four weeks, all three types of weed plant have for the most part withered. The winter barley exhibits a slight growth depression, but then grows normally Without damage.

Example 11 Beetroot and onions are sown in a cultivated area. After the plants have sprouted (height of growth 5 to 10 cm.) 1-phenyl-4-chloroacetylamino 5 chloropyridazone-(fi) is sprayed on the beetroot and onion plants in an amount equivalent to 3 kilograms of active substance per hectare dispersed in 1,000 liters of water. Four to five weeks later, the cultivated plants are growing well. The effect on the weeds after the same period may be seen from the following table which gives the number of weed plants ascertained in each case; the numbers are average values of sixteen repetitions.

TABLE Area treated with 3 kg. per hectare of active substance Untreated Weed control area Chenopodiam album Stellaria media Polygonum persicaria Cruciferae Galinsoga parviflora. matricar Urtica wens Papaver rhoeas Lalium amplrzzcaula. Rumex acetosella.- Ave'na fatua Other grasses SQQJNDHIANOOOJ Total Example 12 wherein R is a substituent selected from the group con- 'sisting of hydrogen, a-hydroxy{3-trichloroethyl, acetyl, ,"chloroacetyl, dichloroacetyl, trichloroacetyl, propionyl, 'chloropropionyl, dichloropropionyl, carbamyl, N-phenyl- )carbamyl and N-3-chlorophenyl-carbamyl.

2. 1-pheny1-4-amino-S-chloropyridazone-(6).

3. 1-phenyl-4 5,5,5 trichloro-a-hydroxy-ethylamino- 5-pyridazone-(6).

4. 1 phenyl 4 chloroacetylamino 5 chloropyridazone-(6).

5. N-phenyl-N'-(1 phenyl 5 chloropyridaz-6-on-4- yl)-urea.

References Cited by the Examiner Druey et a1., Helvetica Chemica Acta. vol. 37 (1954), pages 522 and 528.

NICHOLAS S. RIZZO, Primary Examiner. 

1. A COMPOUND OF THE FORMULA 